Sometimes I don't even know where to start....
Food... LOTS of fresh veggies, a tiny amount of seed, and very little pellet (pionus have vastly different dietary requirements than other psitticines. A good diet makes a healthy happy bird (or at a start)
Cage.... One of the biggest mistakes made by pet bird owners is over furnishing a cage. 3 perches of varying size, and a few toys (give him room to move if you haven't already).
Cage placement..... a cage should be against a wall (two walls like a corner for a nervous bird), and only one wall for a slightly more outgoing bird)... no round cages (birds like to sleep in a corner makes them feel safe)
Lighting.... all birds should either be outside for the majority of the day or a uvb full spectrum light placed over their cage.... replace bulb every six months.
Now those are the basics.... as far as your bid is concerned, consider this.... certain species need very confident handlers, even some individual birds have to be sure that you are the alpha...
I'll put it this way.... ever seen the lady in the grocery store with a whining child or one just being a brat???? THAT lady generally does VERY poorly with parrots. If you can't set firm and fair rules while still loving your bird, then they will do one of two things.... become insanely distrusting, or overtly aggressive.
Do not fear a bird bite (yes they hurt, and I should know I've been bitten countless times over the past 25 years).... but here I refuse to be afraid...
Let me add this, my husband has VERY tough skin on his hands. No grey or pionus or amazon can draw blood. Anytime I have a bird like that I hand it to him.... You'd be amazed how a bird will react if you allow them to bite you and you DON'T react. They generally look a little lost and then you see confusion flash through their eyes, and then a little bit of fear, and then they generally calm right down. So if he does get ahold of you, the advice above about not reacting was sound advice.
Spray bottles have their place, I don't usually recomend them simply because I have seen too many people make some nuerotic birds by sparying them (especially cockatoos). Though it can be a handy training tool in certain cases.
Best of luck!